scholarly journals A negative feedback mechanism in the insulin-regulated glucose homeostasis in Japanese flounder Paralichthys olivaceus by two ways of glucose administration

2017 ◽  
Author(s):  
Dong Liu ◽  
Dongdong Han ◽  
Benyue Guo ◽  
Kangyu Deng ◽  
Zhixiang Gu ◽  
...  

AbstractThe present study comparatively analyzed the blood glucose and insulin concentration, the temporal and spatial expression of brain-gut peptides and the key enzymes of glycolysis and gluconeogenesis in Japanese flounder by intraperitoneal (IP) injection and oral (OR) administration of glucose. Samples were collected at 0, 1, 3, 5, 7, 9, 12, 24 and 48h after IP and OR, respectively. Results showed that the hyperglycemia lasted 5 hours and 21 hours in OR and IP group, respectively. The serum insulin concentration significantly decreased (1.58±0.21mIU/L) at 3h after IP glucose. However, it significantly increased at 3h (3.37±0.34mIU/L) after OR glucose. The gene expressions of prosomatostatin, neuropeptide Y, cholecystokinin precursor and orexin precursor in the brain showed different profiles between the OR and IP group. The OR not IP administration of glucose had significant effects on the gene expressions of preprovasoactive intestinal peptide, pituitary adenylate cyclase activating polypeptide and gastrin in the intestine. When the blood glucose concentration peaked in both IP and OR group, the glucokinase expression in liver was stimulated, but the expression of fructose-1,6-bisphosphatase was depressed. In conclusion, brain-gut peptides were confirmed in the present study. And the serum insulin and the brain-gut peptides have different responses between the IP and OR administration of glucose. A negative feedback mechanism in the insulin-regulated glucose homeostasis was suggested in Japanese flounder. Furthermore, this regulation could be conducted by activating PI3k-Akt, and then lead to the pathway downstream changes in glycolysis and gluconeogenesis.

1995 ◽  
Vol 41 (4) ◽  
pp. 36-38
Author(s):  
Ye. V. V. Naumenko ◽  
A. V. Amikishiyeva ◽  
L. I. Serova

The role of gamma-aminobutyric acid (GABA) of the brain and its receptors in the hypothalamo-pituitary-testicular (HPT) regulation by the negative feedback mechanism was for the first time studied in sham-operated and unilaterally castrated adult Wister rats. Increased level of GABA in the central nervous system following an injection of GABA transaminase inhibitor, aminoacetic acid, into the lateral ventricle of the brain was associated with activation of a compensatory increase of testosterone level in the blood, caused by unilateral castration. GABA effect is mediated through the receptors. Muscimol stimulation of GABA-A receptors of the central nervous system activated and their blocking with bicucullin inhibited a compensatory increase of testosterone level in the blood caused by hemicastration. Baclofen stimulation of cerebral GABA-B receptors was associated with an inhibition and their saclofen blocking with stimulation of the level of male sex steroid hormone in the blood following unilateral castration. A conclusion is made about participation of GABAergic mechanisms of the brain in the regulation of HPT function via the negative feedback mechanism


2008 ◽  
Vol 457 (6) ◽  
pp. 1351-1360 ◽  
Author(s):  
M. Düfer ◽  
D. Haspel ◽  
P. Krippeit-Drews ◽  
L. Aguilar-Bryan ◽  
J. Bryan ◽  
...  

2013 ◽  
Vol 10 (81) ◽  
pp. 20121009 ◽  
Author(s):  
Tomer J. Czaczkes ◽  
Christoph Grüter ◽  
Francis L. W. Ratnieks

Crowding in human transport networks reduces efficiency. Efficiency can be increased by appropriate control mechanisms, which are often imposed externally. Ant colonies also have distribution networks to feeding sites outside the nest and can experience crowding. However, ants do not have external controllers or leaders. Here, we report a self-organized negative feedback mechanism, based on local information, which downregulates the production of recruitment signals in crowded parts of a network by Lasius niger ants. We controlled crowding by manipulating trail width and the number of ants on a trail, and observed a 5.6-fold reduction in the number of ants depositing trail pheromone from least to most crowded conditions. We also simulated crowding by placing glass beads covered in nest-mate cuticular hydrocarbons on the trail. After 10 bead encounters over 20 cm, forager ants were 45 per cent less likely to deposit pheromone. The mechanism of negative feedback reported here is unusual in that it acts by downregulating the production of a positive feedback signal, rather than by direct inhibition or the production of an inhibitory signal.


2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Damian G Romero ◽  
Maria W Plonczynski ◽  
Licy L Yanes ◽  
Tanganika R Washington ◽  
Gina Covington ◽  
...  

Blood ◽  
2013 ◽  
Vol 121 (19) ◽  
pp. 3843-3854 ◽  
Author(s):  
Antonella Teramo ◽  
Cristina Gattazzo ◽  
Francesca Passeri ◽  
Albana Lico ◽  
Giulia Tasca ◽  
...  

Key PointsIn T-LGLL, autologous LGL-depleted PBMCs release high levels of IL-6 contributing to the constitutive STAT3 activation in leukemic LGL. Leukemic LGLs show SOCS3 down-modulation, which is responsible for lack of the negative feedback mechanism controlling STAT3 activation.


1979 ◽  
Vol 55 (6) ◽  
pp. 776-786
Author(s):  
Masatomo MORI ◽  
Kihachi OHSHIMA ◽  
Sakae MARUTA ◽  
Hitoshi FUKUDA ◽  
Yohnosuke SHIMOMURA ◽  
...  

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